Gaps Appearing Within UV Map
It looks to me that certain marked edges get altered with your Multires/Catmull-Clark modifier: the "new" faces created by that seem to be misplaced to the white areas of the texture that you are using. 

I would suggest that first you check for the split edges. I might be terribly wrong, but it looks like you have them on your sleeve... and body too. 

It's very easy to miss and set *Mark Sharp" instead of Mark Seam, for instance, and then as you set multires or subsurf modifiers, edges marked sharp are getting split, which, among other things, means that integrity of the UV is violated.

Also kindly check doubles (Edit Mode > W > Remove Doubles). 

I would also suggest that after you have done it you could try applying your multires modifier for testing purposes and check the exact position of UV for the "white" faces on the hands. Blender now allows both selecting faces in the 3D Viewport and seeing them on your UV in the UV/Image editor, but vice versa too. There is a button "Keep UV and edit mode mesh selection in sync". 

Hopefully this would help.